Police are investigating why a Sudbury man drove his car more than 600 feet across Willis Pond early Thursday morning.

Both he and his passenger, a woman, were taken to Emerson Hospital as a precaution after they were pulled from the Toyota sedan whose front end had broken through the ice.

Police spokesman Lt. Scott Nix said the man and woman, both in their 20s and not identified, live in Sudbury.

He said the car went onto the pond on one side around 12:45 a.m., and drove about 610 feet, nearly making it to the other bank before the ice broke.

"The individuals tried to make arrangements to get it out themselves," Nix said.

It is still not known why the pair drove onto the ice, Nix said.

"It’s still under investigation as far as the exact circumstances of why they brought the car out there," he said.

In the morning, firefighters extended a tow truck hook across the pond to pull the car from the water, but they were unsuccessful. Assistant Fire Chief John Whalen said a special piece of equipment was needed to get the car from the ice.

David Fouquette of Big Wheel Truck Sales in East Freetown and Teddy Negoshian of Negoshian Towing in Newton, pulled the car from the pond using an 25,000-pound hydraulic winch on a Bombadier track machine. The track machine then dragged the car through a marshy area back to shore. According to Negoshian, the hook from shore could have ripped the car apart or led to the car faling through the ice so it was decided to use the all-terrain vehicle.